The fabrication of electrical cables is becoming more sophisticated as specialized electrical requirements are becoming more commonplace. One of the specialized requirements includes the need for a shielded electrical cable having a reduced system generated electromagnetic pulse effect. This pulse effect is significantly amplified in cabling containing internal voids. Such voids are particularly noticeable in cabling containing braided shielding, whose interleaved checkerboard pattern provides wide internal gaps after a surrounding insulative jacket is applied.
In order to fill these gaps, a silicone rubber gum was extruded around and between the lead wires prior to applying the braided shielding. However, the pulse effect was not eliminated because a number of internal spaces were still present with this fabrication method.
The invention resolved the problem by applying a two-part silicone rubber material comprising a rubber base and catalyst under pressure to the extrusion cavity. The two-part system had sufficient viscosity and thixotropic properties, including an acceptable curing time, such that it could be introduced under sufficient pressure in order to fill all of the internal voids between the wire leads and in the shield spaces. The resultant cable product was substantially free of all internal voids, thus greatly reducing system generated electromagnetic pulse effects therein.